1. Field of the Invention
The present invention relates to slide mechanisms, and more particularly to a slide mechanism for a slide-type terminal device.
2. Discussion of the Related Art
Sliding mechanisms are widely used in slide-type terminal devices, such as sliding-type mobile phones and sliding-type personal digital assistants (PDAs). The slide-type terminal device usually has two housings. One housing slides over the other housing, thereby opening or closing the terminal device.
Referring to FIG. 4, a typical sliding mechanism generally includes a first sheet 11, a second sheet 12, and a sliding module 13 for linking the first and the second sheets 11, 12. The first sheet 11 is slidable relative to the second sheet 12. The first and the second sheets 11, 12 are fixed on a display unit and a main unit correspondingly, of a slide-type terminal device. The sliding module 13 includes a first linking member 131, a first pivot shaft 132, a second linking member 133, a second pivot shaft 134, a first sliding sleeve 136, a second sliding sleeve 138, and a spring 139. The first linking member 131 is rotatably attached to the first sheet 11 by the first pivot shaft 132, and the second linking member 133 is rotatably attached to the second sheet 12 by the second pivot shaft 134. An end of the first sliding sleeve 136 is fixed to the first linking member 131, and an end of the second sliding sleeve 138 is fixed to the second linking member 133. Another end of the second sliding sleeve 138 opposite to the second linking member 133 is inserted into the first sliding sleeve 136. The spring 139 is received in the first and the second sliding sleeves 136, 138. A first end of the spring 139 is fixed to the first linking member 131 and a second end of the spring 139 opposite to the first end is fixed to the second linking member 133.
When the display unit is in a closed position, the first sheet 11 is positioned at a first end of the second sheet 12 and the spring 139 is slightly compressed. In an opening process, the display unit is slid opened by an external force from the main unit, the first sheet 11 moves towards a second end opposite to the first end of the second sheet 12, the spring 139 gradually compresses thereby accumulating potential energy and the second sliding sleeve 138 is further slid into the first sliding sleeve 136. The first and the second sliding sleeves 136, 138 are also rotated relative to the first and pivot shaft 132, 134 correspondingly. When the first sheet 11 reaches a middle position of the second sheet 12, the spring 139 is compressed to a shortest length and the second sliding sleeve 138 are fully slid into the first sliding sleeve 136. Because the first sheet 11 passes the middle position of the second sheet 12, the potential energy of the spring 139 creates an elastic force to push the first sheet 11 to slide further until the first sheet 11 is fully opened relative to the second sheet 12. The process of closing the display unit with the first sheet 11 and the above-described opening process are substantially in the same manner.
However, the spring 139 is compressed to a shortest length in the middle position and creates a largest force to the first sheet 11 when passing the middle position, thus the first sheet 11 easily wobbles with the sliding mechanism. Therefore, the sliding first sheet 11 does not slide stably relative to the second sheet 12. In addition, the first and the second sliding sleeves 136, 138 increase a thickness of the slide mechanism.
Therefore, a new slide mechanism which overcomes the above-described shortcomings is desired.